Hey @rik, if you build iodeOS ROMs for Pixel devices and use an Pixel 3a XL bonito yourself, you should know the update option Local update, which has been available since iodeOS 5.x.!
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Manuel update : A manual update can be carried out very easily without a PC and without data loss directly on the device via local update. The *.zip file downloaded directly to the ‘kirin’ is imported by the system and the update can be started. The procedure is as simple as with the OTA update.
Is there also a chance that your Pixel ROMs will receive an avb_custom_key-*****.bin to be able to relock bootloader again?
PS: Thank you for building your iodeOS ROMs, @rik